The invention relates to a
composite coating, a preparation method thereof and a sanitary product. The preparation method of the
composite coating comprises the following steps: forming the
metal base layer on the surface of the base material; n B
layers and n C
layers are formed on the surface of the
metal base layer, and a
composite coating is prepared; wherein n is larger than or equal to 1, the n B
layers and the n C layers are alternately arranged in the thickness direction of the composite
coating, the B layer closest to the
metal base layer is closer to the metal base layer than the C layer closest to the metal base layer, the materials of the B layers comprise Ti and SiO, the materials of the C layers comprise TiOx and SiOy, the C layers are formed in a sputter
coating mode, and the thickness of the C layers is smaller than that of the C layers. The
negative bias voltage is switched between a first
negative bias voltage and a second
negative bias voltage once every 180-480 s, the first negative bias voltage is smaller than or equal to 100 V, and the second negative bias voltage is larger than or equal to 800 V. According to the preparation method of the composite
coating, the scratch resistance of the coating is improved, the service life is prolonged, and the composite coating has excellent waterlogging resistance.